Notable constructivist influences are detectable (e.g. Hegel 1969; Kant 1999; Darwin 1998) as one approaches Piaget’s chosen term for his synthetico-empirical theory (see Piaget 1972) for the study of the acquisition and growth of knowledge – genetic epistemology (Épistémologie génétique). More commonplace is perhaps the intimate relation (Piaget 1952; 1954; 1973) said to be coextensive between what we perceive and how we act; and conversely, what we act upon and how we perceive.